3.6R head gasket job, timing chain? tensioners?

[Snow]

Hello-- I have a 2010 Legacy sedan 3.6R. I got it used from a friend. It has 135K on it and I've just been told the head gasket needs to be done. It's leaking coolant and oil. Seems a bit low mileage for this, but I trust my mechanic. My question is whether or not I should also do the timing chains and tensioners, too? Seems smart since the engine will be out, but they are quite expensive and I've heard from one source that they don't usually have problems. Would appreciate any and all thoughts on this.

Thank you!
Snow